General Advisory for Friday, 12-21-2012

This is a GENERAL AVALANCHE ADVISORY.  A new General Advisory will be issued if conditions warrant or within 72 hours of this release.  This General Advisory pertains to both Tuckerman and Huntington Ravines.

A General Advisory is issued when there are limited instabilities within the entire forecast area. However, there are snowfields that are growing in size and may be unstable. Some examples in Tuckerman include Left Gully, the Chute and the smaller snowfields scattered between ice bulges across the Center Bowl. Some unstable slabs may be poorly bonded to the blue water ice below. Similar conditions may exist in the typical areas of water ice in the narrow Huntington gullies. Assessing snow stability for yourself as you travel through the mountains is always the right thing to do. Keep in mind that avalanche activity may occur before the issuance of a 5-scale forecast and if a snowfield is big enough to recreate on, it’s big enough to avalanche.

It sure has been a week filled with precipitation of all kinds. The higher summits picked up mostly snow with a bit of rain and sleet. Over the last 5 days the summit reports 16.2” (41cm) of snow and mixed precipitation for a total of 2.32” (6cm) of melted water. Snow began on the mountain on Friday in the very early morning. As of this writing, 5” (13cm) has fallen with winds from the south exceeding 70mph (112kph). Unfortunately, we expect most avalanche terrain will see some rain falling on top of the new snow. Rain on snow raises a lot of red flags for travel, even when snowfields are on the smaller side.

Over the weekend you can expect falling temperatures to turn precipitation back to snow. Winds are forecasted to become quite strong on Friday and Sunday, doing a fairly typical transition from a southerly flow on Friday to a more northwesterly direction Saturday and Sunday. The winds may move some newly fallen snow into avalanche terrain, so again I’d advise you to be prepared to make your own snow stability assessments as you travel in avalanche terrain.

At this time of the year new snowfall can make a remarkably rapid change in potential avalanche conditions, so start paying attention to the daily weather and new snow amounts. Be sure to check for the latest avalanche advisory before heading into avalanche terrain. Have a great ramp up into the holidays and maybe we’ll see you up here soon.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This advisory is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
  • Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast.
  • For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or the Harvard Cabin. Posted 0930 12-21-2012. A new advisory will be issued when conditions warrant.

Jeff Lane, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

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